An Universal Cracking Amount Model for Fatigue, Reflective, Thermal and Top-down Cracking
主讲人：Dr. Fujie Zhou
邀请人：孙立军、刘黎萍教授
时间：2016年12月6日（周二）14:00-16:00
地点：交通运输工程学院103会议室
主讲人简介
Dr. Zhou graduated from Tongji University in 1998. He currently works at the Texas A&M Transportation Institute (TTI). He has over 18 years of research experience in the field of asphalt pavements. His professional interests include asphalt pavement design, modeling and performance prediction (rutting, fatigue cracking, reflection cracking, low-temperature cracking, top-down cracking), and asphalt overlay rehabilitation of existing flexible and PCC pavements, balanced mix design, RAP/RAS characterization, laboratory characterization of HMA mixes and asphalt binders. In 2004, he received the Texas Department of Transportation’s Top Innovations Award for his work on the Texas Overlay Test. He won two times the Walter J. Emmons Award for the best papers presented at AAPT 2010 and 2014 regarding asphalt overlay ME design system and balanced RAP/RAS mix design system. He has published more than 40 peer-reviewed papers and numerous technical reports. His most recent work on cracking tests, ME pavement design, rejuvenators, RAP and RAS, asphalt overlay design, balanced mix design, and the Overlay Test was published in the journal of the Association of Asphalt Paving Technologist (AAPT) 2005, 2007, 2008, 2010, 2012, 2013, 2014, 2015 and 2016 and the Transportation Research Board 2007, 2010, 2011, 2013, 2014, and 2016. Dr. Zhou has been PI and Co-PI for many TxDOT’s research projects and NCHRP projects.
主讲内容简介
There is a national and international movement to develop Mechanistic-Empirical (M-E) methods for the design of flexible pavements. The presenter will discuss current ME design and analysis frameworks which have a very weak link: cracking amount model connecting pavement damage (predicted from mechanistic analyses) to pavement cracking distresses. The importance of cracking amount models has not received the deserved attention. After reviewing all the available existing cracking amount models, a universal cracking amount model was proposed for all four cracking modes: fatigue, reflective, thermal, and top-down cracking. The new model governed by two parameters (a and b) naturally fits into the overall ME design system. Parameter a is pavement life which can be directly predicted from the ME analysis since it is the time (or number of load applications) when accumulated pavement damage is 100 percent. Parameter b is shape parameter that is function of traffic, environment, subgrade, pavement structure and material properties, and existing pavement conditions for asphalt overlays. Thus, the key of the new model is to establish specific quantitative b functions for fatigue, reflective, thermal, and top-down cracking, respectively, since the parameter a is already addressed by ME design and analysis systems.
Both fatigue cracking data in the national LTPP database and asphalt overlay reflective cracking data in Texas were used to demonstrate and calibrate the new model and develop the quantitative b functions. Different b functions were established for fatigue and reflective cracking, respectively. However, further model validation and calibration with more field data, varied traffic load spectra, different environmental conditions, and different materials are still required. Additionally, the cracking amount models for thermal and top-down cracking should be pursued when consistent field cracking data are available.
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